Good Lecturers Can Make You Overconfident

A few days ago I complained that the problem with TED lectures is that they sometimes seem to favor skillful speaking at the expense of quality content. From Christian Jarrett, here’s a description of a research study that gives us one more reason to be suspicious of TED talks.

After watching the video, the students rated how well they thought they’d do on a test of its content ten minutes later. The students who’d seen the smooth lecturer thought they would do much better than did the students who saw the awkward lecturer, consistent with the idea that a fluent speaker breeds confidence. In fact, both groups of students fared equally well in the test. In the case of the students in the fluent lecturer condition, this wasn’t as good as they’d predicted. Their greater confidence was misplaced.

This has at least two implications for TED.

First, even if it makes sense to recruit competent speakers, TED probably doesn’t need to prioritize style quite so heavily. After all, this study suggests that being a fluent speaker may not add much value in terms of informing listeners.

Second, TED speakers are – almost by definition – discussing the “bleeding edge” of their field or attempting to synthesize knowledge from diverse fields in novel ways. That’s exactly the kind of information that justifies less certainty, not more. It’s completely standard in a TED talk to convey far more confidence about their ideas than is justified by the evidence. This study suggests speakers can generate that same excessive certainty in their audiences.

And teachers can take heart, too: You don’t need to be a virtuoso speaker to be a good teacher. Indeed, such skill can even be a liability in some cases.